Characterizing dominant climatic oscillations in Antarctic Surface mass balance

Thursday, 18 December 2014
Kishore Pangaluru, University of California, Irvine, CA, United States, Isabella Velicogna, University of California Irvine, Irvine, CA, United States, Tyler C Sutterley, University of California Irvine, Department of Earth System Science, Irvine, CA, United States and Michiel R van den Broeke, Utrecht University, Utrecht, Netherlands
We use 34 years (1979-2012) of monthly surface mass balance (SMB) from the RACMO regional atmospheric climate model to evaluate the main oscillations characterizing the SMB signal in West Antarctica (WAIS) and East Antarctica (EAIS). For each region we use the empirical mode decomposition (EMD) analysis to decompose SMB signal into locally periodic components (IMFs), and we determine the dominant oscillation characterizing each IMF time series using the Lomb-Scargle Periodogram analysis. To study the time variable amplitude of the identified oscillations we apply a wavelet analysis to each monthly IMF time series. In both regions we are able to identify the main climatic oscillation such as semi-annual oscillation (SAO), annual oscillation (AO), quasi-biennial oscillation (QBO), El Nino-Southern Oscillation (ENSO) and a decadal cycle. In WAIS we find that the amplitude of the QBO is largest in 2004-2010. In EAIS QBO is statistically significant after 1994 with larger amplitude in 1994-2004. In WAIS we find a statistically significant ENSO during 1979-1999 with the largest signal during 1984-1994. In EAIS we detect a statistically significant ENSO signal during 2003-2011. In EAIS most of the SMB signal comes from the coastal regions, however we can also detect the signature of these oscillations in the interior.